URUG 2015-06-23 Trigram Kata - check out: github.com/urug/trigram_kata

generator.rb

module Generator
  def self.generate(trigram, prompt, size)
    content = prompt.split(' ')

    while content.length < size
      new_word = trigram.get content[-2..-1].join(' ')
      content << new_word
    end
    
    content.join(' ')
  end
end

trigram.rb

class Trigram
  attr_reader :text

  def initialize(text)
    @text = text
    build_dict
  end

  def get(two_words)
    @dict[two_words].sample
  end
  
  private
  
  def build_dict
    @dict = Hash.new {|hsh,key| hsh[key] = []}
    @text.split(' ').each_cons(3) {|a,b,c| @dict["#{a} #{b}"] << c}
  end    
  
  def build_dict2
    @dict = Hash.new
    @text.split(' ').each_cons(3) do |a,b,c|
      key = "#{a} #{b}"
      @dict[key] ||= []
      @dict[key].push c
    end
  end    
end